Here's a question for you: if intelligent life roughly fitting the parameters, capabilities, resources, and interests of human beings was at all common in the universe, how come we've never seen any evidence of it? Likewise with FTL travel. If it's possible to travel faster-than-light and it requires a level of technology that we can conceive (meaning alien civilizations capable of it should be ubiquitous), we should be getting visitors all the time, or at least detecting some really odd (inexplicable) characteristics in space where there's any FTL going on.

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If I did not know better, I would assume you were one of those people completely clueless about how big the universe really is. Hell, just on our tiny planet how long did Native Americans go before they saw any evidence of other people from other continents? Some time. When we multiply that scale by a nearly unfathomable number and couple that with the fact that we have only taken one or two figurative steps into space, the answer to your question is rather obvious.

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I was making the point that if the assumptions being made were commonplace (life->complex life->intelligent life->space exploration->FTL travel) then we'd see it everywhere because it's had ~15 billion years to develop. The Milky Way alone would have many thousands if not millions of intelligent species. That we have seen absolutely no evidence of this indicates that intelligent, technologically advanced, spacefaring life is either quite rare or not contemporaneous.

^ But like I said, why would aliens WANT to come to Earth? Any alien species that has the technology to even reach Earth in the first place is probably not going to consider us worth the trip. We would be the equivalent of trailer-park trash to them. So why would they bother?

^ But like I said, why would aliens WANT to come to Earth? Any alien species that has the technology to even reach Earth in the first place is probably not going to consider us worth the trip. We would be the equivalent of trailer-park trash to them. So why would they bother?

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Where did I ever say they needed to come to Earth? We have a lot of telescopes pointed at the sky, which are getting more powerful all the time, and we've never seen even one tiny shred of evidence for intelligent life outside Earth.

If there is intelligent life out there, there is some reason we haven't found it: it's too far away (meaning it is relatively rare), it is not capable of interstellar flight (which means it is difficult enough that hardly anyone can do it), or it simply never exists contemporaneously with us (again, pointing to the rarity or at least short-lived nature of such civilizations.)

Where did I ever say they needed to come to Earth? We have a lot of telescopes pointed at the sky, which are getting more powerful all the time, and we've never seen even one tiny shred of evidence for intelligent life outside Earth.

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Primitive Earth technology.

If there is intelligent life out there, there is some reason we haven't found it: it's too far away (meaning it is relatively rare)

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It's an infinite universe. There's plenty of room. There could be a hundred intelligent federations out there and yet be so far apart that they'd never encounter each other in a billion years.

it is not capable of interstellar flight (which means it is difficult enough that hardly anyone can do it), or it simply never exists contemporaneously with us (again, pointing to the rarity or at least short-lived nature of such civilizations.)

Not even close. The best you could say is that 3D printing technologies have the potential to EVENTUALLY develop into Von Neuman machines at some point in the future, but there are certain fundamental limitations to that technology that are nowhere near to being transcended.

there are even patents that exist now for some self-replicating technology...

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That's kind of amazing, considering there's no such thing as "self-replicating technology" right now.

using fabrication technologies at the forefront of advancements right now...

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The only technologies that would allow for that are all theoretical at best.

Regardless, the original point in my first post still stands....there are ways that could be effective to spread civilization through space without exotic technologies, they are both easier and more likely, and nothing that couldn't exist given a little time.

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1) Self-replicating technology IS an exotic technology by any normal standards, especially considering the technical challenges of making it really feasible (unless those machines operate with a LOT of direct participation from their builders, which even the most far-out concepts still assume as a matter of course).
2) They probably wouldn't be easier to manufacture considering what they're being asked to do in the field, even with the support of their manufacturers.
3) To say they are more likely is, again, a really longshot assumption, considering the principle use of self-replicating machines is to exploit tightly packed resources in difficult environments, and interplanetary/interstellar space is anything but.

If I did not know better, I would assume you were one of those people completely clueless about how big the universe really is. Hell, just on our tiny planet how long did Native Americans go before they saw any evidence of other people from other continents? Some time. When we multiply that scale by a nearly unfathomable number and couple that with the fact that we have only taken one or two figurative steps into space, the answer to your question is rather obvious.

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I was making the point that if the assumptions being made were commonplace (life->complex life->intelligent life->space exploration->FTL travel) then we'd see it everywhere because it's had ~15 billion years to develop. The Milky Way alone would have many thousands if not millions of intelligent species. That we have seen absolutely no evidence of this indicates that intelligent, technologically advanced, spacefaring life is either quite rare or not contemporaneous.

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That's a double assumption of your own, though:
1) That if you can travel faster than light, you can travel at ANY speed to ANY location with relative ease.
2) That an intelligent species developing a hugely advanced spacefaring civilization WOULD develop FTL travel even if it were possible.

Neither has a lot of support; a drive system that could achieve FTL velocities might require many hours or even months to build up that kind of velocity, which would still limit interstellar travel to either large highly expensive generation ships or to small unmanned probes with limited range and capabilities. Such a civilization might be tempted to explore beyond their own solar system, but to COLONIZE beyond it could still be impossible or infeasible at any level of advancement.

Secondly, just because something is possible doesn't mean it is discoverable. The Chinese, for example, were the first to develop gunpowder but only recently began developing practical manned spaceflight. By the same token, even if FTL travel is possible, FTL spaceflight is a whole different ballgame and conditions may not exist in all civilizations that make it even worth exploring.

^ But like I said, why would aliens WANT to come to Earth? Any alien species that has the technology to even reach Earth in the first place is probably not going to consider us worth the trip. We would be the equivalent of trailer-park trash to them. So why would they bother?

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Where did I ever say they needed to come to Earth? We have a lot of telescopes pointed at the sky, which are getting more powerful all the time, and we've never seen even one tiny shred of evidence for intelligent life outside Earth.

If there is intelligent life out there, there is some reason we haven't found it: it's too far away (meaning it is relatively rare), it is not capable of interstellar flight (which means it is difficult enough that hardly anyone can do it), or it simply never exists contemporaneously with us (again, pointing to the rarity or at least short-lived nature of such civilizations.)

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How would telescopes help in finding evidence of extra solar civilizations? By detecting interstellar ships in transit? Even if their ships were the size of sodding Jupiter, and were flying through the Proxima Centauri system we wouldn't be able to detect them.

Radio telescopes are probably a better bet, but you have to be pointing them in exactly the right direction, at exactly the right time and happen to be monitoring exactly the right frequency. And the thing about space (altogether now!) space, is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen...

I know that it's a bit of an 'invisible dragon' argument, but realistically speaking: saying there's nothing out there because we haven't found any evidence rather fails to take into account our almost total inability to detect anything smaller than a star until it's right on top of us.
I do agree however that while the odds are pretty good that we weren't the first forms of life to achieve some form technological civilization (maybe not even the first on this planet) nor will we be the last, the odds are about as good that no two are ever likely to detect one another given the vast distances and stretches of time involved.

For all we know there could have been a spacefaring race not 100 lightyears from here (so close on the cosmic scale as to practically occupying the same point in space) but we'll never know because they got hit by an comet and wiped out 200 years ago.

I think there's only two or three ways we're likely to get 100% solid proof of an alien civilization: Either one of us randomly stumbles on the other (or our respective ruins/space junk) or by some utter fluke SETI actually picks up the alien equivalent of Jazz FM.

But still, like I said, for all we know we *could* be in the more densely populated star cluster, of the most densely populated spiral arm of the most densely populated galaxy in the universe and there'd be no way we'd even know.Claiming otherwise would be like standing atop your horse drawn cart the the middle of the sahara, peering at the horizon and proclaiming that since there's no evidence of them, Eskimos can't possibly be out there.

But, again, I never said there was "nothing" out there, just that whatever may be out there is rare enough that, after decades of scanning the skies, we've found... nothing. The universe may even be teeming with life, with virtually none of it more advanced than fungi. It's even possible for a world to have numerous highly intelligent species that are nevertheless not capable of developing spacefaring technology. Do you see dolphins or elephants or pigs building rockets? They are at least as smart as us, but evolved in a manner that precludes the creation and use of complex tools.

I don't think it's unreasonable to be skeptical of claims that the universe is full of intelligent, spacefaring life forms, especially when you come up against comments suggesting that Von Neumann probes are almost within reach. Given that they are a fairly straightforward idea, the universe should be positively crawling with them if anyone had ever built them.

I also think it's essentially irrelevant if intelligent, spacefaring life exists but it is much too far away for us to ever encounter or even discover it. It might as well not exist, as a practical matter.

Not even close. The best you could say is that 3D printing technologies have the potential to EVENTUALLY develop into Von Neuman machines at some point in the future, but there are certain fundamental limitations to that technology that are nowhere near to being transcended.

there are even patents that exist now for some self-replicating technology...

Click to expand...

That's kind of amazing, considering there's no such thing as "self-replicating technology" right now.

using fabrication technologies at the forefront of advancements right now...

Click to expand...

The only technologies that would allow for that are all theoretical at best.

Regardless, the original point in my first post still stands....there are ways that could be effective to spread civilization through space without exotic technologies, they are both easier and more likely, and nothing that couldn't exist given a little time.

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1) Self-replicating technology IS an exotic technology by any normal standards, especially considering the technical challenges of making it really feasible (unless those machines operate with a LOT of direct participation from their builders, which even the most far-out concepts still assume as a matter of course).
2) They probably wouldn't be easier to manufacture considering what they're being asked to do in the field, even with the support of their manufacturers.
3) To say they are more likely is, again, a really longshot assumption, considering the principle use of self-replicating machines is to exploit tightly packed resources in difficult environments, and interplanetary/interstellar space is anything but.

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We were discussing how an alien species might circumvent the vast distances of space without exotic ftl drives in the context of the long period of stellar time available for those aliens to develop such technology.

Yes, it is a fact that elements of technology that need to exist for self-replication are already patented. There are also organizations involved in planning and use of the technology. It's not quite as far off as you seem to think..The AI required would be sophisticated, but simple compared to what we would consider for The Singularity.

The technologies being studied include 3D printing type technologies, and are hardly purely theoretical. Here are just some examples I've come across:

But, again, I never said there was "nothing" out there, just that whatever may be out there is rare enough that, after decades of scanning the skies, we've found... nothing. The universe may even be teeming with life, with virtually none of it more advanced than fungi. It's even possible for a world to have numerous highly intelligent species that are nevertheless not capable of developing spacefaring technology. Do you see dolphins or elephants or pigs building rockets? They are at least as smart as us, but evolved in a manner that precludes the creation and use of complex tools.

I don't think it's unreasonable to be skeptical of claims that the universe is full of intelligent, spacefaring life forms, especially when you come up against comments suggesting that Von Neumann probes are almost within reach. Given that they are a fairly straightforward idea, the universe should be positively crawling with them if anyone had ever built them.

I also think it's essentially irrelevant if intelligent, spacefaring life exists but it is much too far away for us to ever encounter or even discover it. It might as well not exist, as a practical matter.

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I only gave 3 of the more likely reasons, there are certainly more. An active or passive prime directive scenario might come into play...

The distance without ftl drives is a good reason to permeate the galaxy with slowly (by slow I mean 100,000s of mph, or a maximum of maybe .5 of speed of light) speading automated machines which can either develop on their own or make way for living beings.

Honestly such discussions are far more interesting to me than anything I'd watch on Ancient Aliens!

^ But like I said, why would aliens WANT to come to Earth? Any alien species that has the technology to even reach Earth in the first place is probably not going to consider us worth the trip. We would be the equivalent of trailer-park trash to them. So why would they bother?

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Where did I ever say they needed to come to Earth? We have a lot of telescopes pointed at the sky, which are getting more powerful all the time, and we've never seen even one tiny shred of evidence for intelligent life outside Earth.

)

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This is not a good reason to dismiss low observable technologies out in space right now like Von Neumann machines, because we routinely miss asteroids that come very close to us, in fact our record at locating just about anything in space is pretty abysmal and only improving slightly in the near future. This is mainly because there aren't many people looking, and we've only been looking with any great alacrity for a few decades in the entire timescale of humanity.

^ But like I said, why would aliens WANT to come to Earth? Any alien species that has the technology to even reach Earth in the first place is probably not going to consider us worth the trip. We would be the equivalent of trailer-park trash to them. So why would they bother?

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Or the reverse is possible...intelligent species that survive self-destruction or poke their heads out after self-obsessed Singularity evolution, may in fact be interested in each and every apparently uncommon intelligent species...but would they want anything from us...probably not. As Carl Sagan put it, aliens might simply be lonely...

Here's a question for you: if intelligent life roughly fitting the parameters, capabilities, resources, and interests of human beings was at all common in the universe, how come we've never seen any evidence of it? Likewise with FTL travel. If it's possible to travel faster-than-light and it requires a level of technology that we can conceive (meaning alien civilizations capable of it should be ubiquitous), we should be getting visitors all the time, or at least detecting some really odd (inexplicable) characteristics in space where there's any FTL going on.

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If I did not know better, I would assume you were one of those people completely clueless about how big the universe really is. Hell, just on our tiny planet how long did Native Americans go before they saw any evidence of other people from other continents? Some time. When we multiply that scale by a nearly unfathomable number and couple that with the fact that we have only taken one or two figurative steps into space, the answer to your question is rather obvious.

Click to expand...

I was making the point that if the assumptions being made were commonplace (life->complex life->intelligent life->space exploration->FTL travel) then we'd see it everywhere because it's had ~15 billion years to develop. The Milky Way alone would have many thousands if not millions of intelligent species. That we have seen absolutely no evidence of this indicates that intelligent, technologically advanced, spacefaring life is either quite rare or not contemporaneous.

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Hell, life in general could exist on a few million planets in the milky way while we have yet to look at or detect any one of them. Who is to say how common place it is for intelligent life to develop FTL (making the rather larger assumption that such a thing is possible)?

I agree that your question would apply if the claim was that life which can travel faster than light is common place and that such travel is so much faster than the speed of light that they could travel to any point in the universe (or galaxy if we confine things to the Milky Way) in a short period of time at relatively low cost/expenditure. But even in such a case, would the FTL races have time or desire to visit everyone? What if there are billions of different planets in the universe with life? Would they get to them all? How many races have FTL ability? 1/100th? 1/1000th? Fewer? And this is all assuming such technology does exist.

If I did not know better, I would assume you were one of those people completely clueless about how big the universe really is. Hell, just on our tiny planet how long did Native Americans go before they saw any evidence of other people from other continents? Some time. When we multiply that scale by a nearly unfathomable number and couple that with the fact that we have only taken one or two figurative steps into space, the answer to your question is rather obvious.

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I was making the point that if the assumptions being made were commonplace (life->complex life->intelligent life->space exploration->FTL travel) then we'd see it everywhere because it's had ~15 billion years to develop. The Milky Way alone would have many thousands if not millions of intelligent species. That we have seen absolutely no evidence of this indicates that intelligent, technologically advanced, spacefaring life is either quite rare or not contemporaneous.

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Hell, life in general could exist on a few million planets in the milky way while we have yet to look at or detect any one of them. Who is to say how common place it is for intelligent life to develop FTL (making the rather larger assumption that such a thing is possible)?

I agree that your question would apply if the claim was that life which can travel faster than light is common place and that such travel is so much faster than the speed of light that they could travel to any point in the universe (or galaxy if we confine things to the Milky Way) in a short period of time at relatively low cost/expenditure. But even in such a case, would the FTL races have time or desire to visit everyone? What if there are billions of different planets in the universe with life? Would they get to them all? How many races have FTL ability? 1/100th? 1/1000th? Fewer? And this is all assuming such technology does exist.

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Oh, but to hear some tell it, any civilization that gets near our level of development will inevitably reach the Singularity, which promises technologies we can't even imagine. At a minimum, there should be Von Neumann probes everywhere, since those are so easy and cheap to build.

One place we can confirm with life so far. On that planet, only once has a sophisticated nervous system resulted in tool using, environment challenging creation so far as we know. Nothing in that technology shows any signs of being able to handle much less overcome a planet wide near extinction event, which has happened several times before and will likely happen again. My optimistic side wants to imagine vast grand life out there which we can one day be a part of, but my rational side just doesn't buy it.

Let's face it guys. There is no tangible evidence that intelligent life exists outside this planet. I will say that given the sheer number of stars in this galaxy and the sheer number of galaxies in the universe that the odds favor life evolving elsewhere. But there's really no way to prove it one way or the other at this time. Or if it would even be anything like us. Just imagine what an evolutionary advantage we humans have, possessing interposable thumbs for example. To say nothing of how differently intelligent beings evolving under different circumstances would view the world as opposed to us.

This is a rather circular debate to have. If there are aliens out there, then how come only rednecks and scifi fanatics see them? :P

One place we can confirm with life so far. On that planet, only once has a sophisticated nervous system resulted in tool using, environment challenging creation so far as we know. Nothing in that technology shows any signs of being able to handle much less overcome a planet wide near extinction event, which has happened several times before and will likely happen again. My optimistic side wants to imagine vast grand life out there which we can one day be a part of, but my rational side just doesn't buy it.

The Fermi paradox:
If only one species masters interstellar flight (NOT FTL, but BELOW LIGHTSPEED flight), then this species will easily colonise the entire galaxy within 100 million years. Also - after it spreads to ~10 solar systems, this species is all but indestructible - no catastrophe can extinguish it any longer.

Well, our galaxy is ~13,6 billion years old - but only since ~6 BILLION years there were enough heavy elements for life to be able to form.
In ~6 BILLION years, if ET advocates are to be believed, many, many intelligent species have arisen. But these advocates always have trouble explaining why none of them managed to send the first few interstellar ships - a feat humanity is close to accomplish (a few hundred/thousand years is a mere blink of cosmic time).
EVERY SINGLE ONE of these species - all the factions with different agendas and actions each species was composed of - always conveniently went extinct or 'insert another solution to the Fermi paradox that badly breaks Occam's razor'.

The most likely solution to the Fermi paradox is either that abiogenesis is very hard/rare (which is heavily supported by the staggering complexity of the simplest molecule that can reliably self-replicate) or that technological intelligence is very hard to evolve.